Remote Control Helicopter Multicopter Spare parts Lipo LiFe LiMn Li-ion Battery Monitor Alarm Low Voltage Buzzer Alarm Indicator 1S-8SFeatures:1. Use for 1-8s Lipo/Li-ion/LiMn/Li-Fe.2. When the voltage is below the set value,it will buzzer with red LED light,pre-set value 3.3V.push key which can change the voltage settings and save.